/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/****************************************************************************
 * libc/libgen/lib_dirname.c
 *
 *   Copyright (C) 2007, 2009, 2011-2012 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <tinyara/config.h>

#include <string.h>
#include <libgen.h>

/****************************************************************************
 * Private Data
 ****************************************************************************/

static char g_retchar[2];

/****************************************************************************
 * Global Functions
 ****************************************************************************/

/****************************************************************************
 * Function: dirname
 *
 * Description:
 *   dirname() extracts the directory component from a null-terminated
 *   pathname string. In the usual case, dirname() returns the string up
 *   to, but not including, the final '/'. Trailing '/' characters are not
 *   counted as part of the pathname.
 *
 *   If path does not contain a slash, dirname() returns the string ".". If
 *   path is the string "/", then dirname() returns the string "/". If path
 *   is a NULL pointer or points to an empty string, then dirname() returns
 *   the string ".".
 *
 *   dirname() may modify the contents of path, so copies should be passed.
 *   dirname() may return pointers to statically allocated memory which may
 *   be overwritten by subsequent calls.
 *
 * Parameter:
 *   path The null-terminated string referring to the path to be decomposed
 *
 * Return:
 *   On success the directory component of the path is returned.
 *
 ****************************************************************************/

FAR char *dirname(FAR char *path)
{
	char *p;
	int len;
	int ch;

	/* Handle some corner cases */

	if (!path || *path == '\0') {
		ch = '.';
		goto out_retchar;
	}

	/* Check for trailing slash characters */

	len = strlen(path);
	while (path[len - 1] == '/') {
		/* Remove trailing '/' UNLESS this would make a zero length string */
		if (len > 1) {
			path[len - 1] = '\0';
			len--;
		} else {
			ch = '/';
			goto out_retchar;
		}
	}

	/* Get the address of the last '/' which is not at the end of the path and,
	 * therefor, must be the end of the directory component.
	 */

	p = strrchr(path, '/');
	if (p) {
		/* Handle the case where the only '/' in the string is the at the beginning
		 * of the path.
		 */

		if (p == path) {
			ch = '/';
			goto out_retchar;
		}

		/* No, the directory component is the substring before the '/'. */

		*p = '\0';
		return path;
	}

	/* There is no '/' in the path */

	ch = '.';

out_retchar:
	g_retchar[0] = ch;
	g_retchar[1] = '\0';
	return g_retchar;
}
